Relief valve



proved relief v effective to teminste the n uid flow is substan- Patented Dec. 3, 1946 Max A. Mathys, Detroit, Mich., asslgnor to Ex- Cell-O Corporation, Detroit, Mich., a corporation of Michigan Application July 14, 1943. Serial No. 494,609

5 claims. (ci. 1stssi The present invention relates in relief valves for fluid pressure systems, and has particular reference to a new and improved valve adapted to divert fluid from a pressure line when the pressure therein tends to rise above a predetermined maximum.

One of the objects of the present invention is to provide a novel relief valve in which the closing pressure is more closely related to the opening pressure than in the case of conventional relief valves of the poppet type or piston type.

Another object is to provide a new and im-` alve in which the closing pressure to improvements tially the same as the opening pressure effective to Iinitiate the fluid flow, said pressures difiering, if at all, only to the slightest possible extent.

Still 'another object is to provide a novel relief valve in which av dynamic force generated as an incident to a change in direction of uid flow through the valve is utilized to supplement the closing pressure of a spring in opposition to the normal opening pressure of the fluid at the inlet acting on the valve member.

Other objects and advantages will become apparent asthe description proceeds. Inthe accompanying drawings,

Figure 1 is a fragmentary view of the hydraulic bodying the features of my invention.

Figs. 2 and 3 are transverse sectional views of ing back to the reservoir I3,

is operable to bypass any excess iiuid so as to one embodiment of the invention adapted primarily for use as a working pressure relief valve in a hydraulic transmission system. For purposes of illustration, the valve Il! is shown connected in a simple system having a pump II taking hydraulic fluid through an intake line I2 from a supply reservoir I3. The pump I-I has a discharge line Il for conducting fluid under pressure to a point of u se, such as a hydraulic actuator (not shown). Y

The valve I0 is connected in the system through an inlet pressure line I! branching from the pump discharge line I4, and an outlet relief line I6 leadand in normal use limit the discharge pressure of the pump to a predetermined adjustable maximum working pres- In its exemplary form, the valve II) comprises a main body I1 preferably cylindrical in shape. One end of the body I1 is formed with a relativelylarge bore I8 constituting a spring chamber and connected through an outlet passage I9 to the relief line Il. A screw plug 20 is adjust-l ably threaded Into the outer endA of the bore I8 to close the latter, and is normally secured in position of adjustment by means of a lock nut 2I threaded thereon against the end of the body transmission system including a relief valve in' longitudinal section and on an enlarged scale em-A the valve taken along lines 2,-2 and 3--3 of Fig. 1.

Fig. 4' is a. longitudinal sectional view of a relief valve constituting amodiiled form of the I Invention.

-Iiig. 5 is a transverse sectional view taken along line 5-5 of Fig. 4.

Fig. 6 is a fragmentary view partially in longitudinal section of a relief valve constituting another modi-fled form of the invention.

Fig. 7 is a transverse sectional view taken along line 1--1 of Fig. 6.

While the invention is susceptible of various modifications and alternative constructions, 1

have shown in the drawings and'will herein describe in detail the preferred embodiment; but it is tobe understood that I do not thereby intend to limit the inventionto the specific form disclosed, but intend to cover al1 modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings, the valve IU shown in Figs. l to 3 constitutes I1. Also threaded onto the outer yend of the screw plug 2li to enclose the latter is a cap nut 22.

The opposite end of the valve body I1 is formed with a vrelatively-small valve bore 23 opening coaxially to the bore I8. The outer end of the valve bore 23 is formed with a counterbore 24 closed by a screw plug 25 and constituting a pressure chamber. face of the valve bore 23 intermediate its ends is an annular groove 2l connected through an inlet passage 21 to the pressure line I5. A restricted snubber channel or passage 28 opens from the passage 21 to the chamber 2| to conduct fluid thereto at the valve inlet pressure.

A sleeve valve member 29 extends through the valve bore 23 with a snug sliding fit. The outer Formed in the inner peripheral sur- 3 valve ports, and are movable out of communication to close the valve I0, and into varying degrees of registration to open the valve. The path of flow through the valve I is from the inlet passage 21 through the ports 2B and 3I, and radially through the ports 32 into the bore 30, and thence at right angles through the bore 3|J and chamber I8 to the outlet passage I9.

The position of the valve member 29 is controlled by a coiled compression spring 33 acting thereon in a direction to close the valve I 0 in opposition to a valve openingr pressure exerted by the fluid at the inletI 21. The fluid ypressure is transmitted from the inlet passage 21 through the snubber passage 28 to the chamber 24 wherein it acts against the end face area of the valve member 29. Thus, the valve opening area is of xed size so that the opening pressure varies only as the pressure of the inlet fluid, and is not directly disposed in the path of fluid iiow through the valve I0.

The spring 33 is disposed within the chamber I8, and seats at the outer end statically against the screw plug about a centering pilot 34. The inner end of the spring 33 engages a spring pilot washer 35 fixed on the valve member 29. The valve closing pressure exerted by the spring 33 may be varied by adjusting the screw plug 20 which is provided with a hexagon head 36 to facilitate such adjustment.

In operation, when the fluid pressure in the inlet line I5 from the discharge line I4 of the pump I I is below the normal working pressure, at which the valve In is set to open, the pressure of the fluid within the chamber 24 acting on the valve member 29 is insufhclent to overcome the force of the spring 33, so that the ports 29 and 3I are completely out of registration to interrupt the bypass or relief of iiuid. As the pressure in the chamber 24 rises, it acts against the valve member 29 to move the port 3| progressively toward and then into varying degrees of registration with the port 25 to open the valve. With the valve in open position, av portion of the iluid from the inlet line I5 is bypassed. The change in direction of flow of the fluid issuing from the radial ports 32 within the bore 30 of the valve member 29 generates a dynamic force which acts inlet passage 45 opening from the bore 31 to a Y transverse bore 46 in turn open to the chamber 24* through a` connecting bore 41, and a ball 48 normally urged by a light compression spring 49 within the bore 43 against a seat 50 at the end of the passage 45.

When the valve Ill*l is to be adapted for pump pressure control to operate in substantially the same manner as the valve I0 of Figs. 1 to 3, the plug 4I is removed and the plug 42 is inserted. The inlet passage 21l is then connected through the bore 31 and the port 43 to the pressure cham-- ber 24a. When the valve I0 is to be adapted, for orifice pressure control, the plug 4I is inserted andthe plug 42 is removed, and the bore 31 is connected to the orifice control line 3'8. In this condition, the passage 21 is blocked from the chamber 24 so that the valve I0' is not responsive to the inlet pressure from the pump discharge line I 5*. In both adaptations, pressure rises are freely transmitted through the check valve 44 to the pressure chamber 24, but in the on the valve member 29 in a direction to supple ment the force oi' the spring 33. Variation in the, volume of flow through the valve will result in a corresponding variation in the dynamic force. Because of the control factors ofthe valve I0, the opening pressure and the closing pressure are approximately the same, and the desired maximum working pressure is effectively maintained' within an extremely small range of variation.

Figs. 4 and 5 illustrate a modied form of relief valve which is convertible for use either as a pump pressure control, as inthe case oi the form of Figs. 1 to 3, or as an orice pressure control. The construction is generally similar to that disclosed in Figs.v 1 to 3, and corresponding parts are, therefore, identified by the same reference numerals, with the added subscript a,

In the modified form of Figs. 4 and 5, the outer end oi' the valve bore 23* does not open to the extreme end of the body I1, but terminates short thereof, and is diametrically enlarged to define the pressure chamber 24B. Formed in the body I1 is a longitudinal bore 31 for connecting the pressure chamber 24' optionally either to the inlet passage 215. or'to an outside line 38 leading from the upstream side of an adjustable pressure control oriilce 39in a line 40. The inner event of a drop in the control pressure the resulting closing movement of the valve member 29 is snubbed or dampened due to the restriction to liid egress from the chamberv through the port In oriilce pressure control, the operation of the valve is responsive to the pressure established in the line 33,by the flow restriction through the oriilce 39. Such orice may be arranged in various types of control systems, for example to receive and meter uid discharging from an actuator which in turn is motivated by fluid under pressure from the pump II, as in the patent to Alden No. 2,000,553.

Figs. 6 and 7 disclose another modied form of the invention which is generally similar to that shown in Figs. 4 and 5 and, therefore, corresponding parts are identified by like reference numerals, with the addition of the subscript "b. In this case,` a valve sleeve 5I is xed in the valve bore 23h to receive the valve member 29h, and is Aformed with an annular groove 52 in communication with the inlet passage 21'?. 'Ihe sleeve 5I is formed with a plurality of peripheral ports 53 opening from the groove 52 to the inner bore for cornmunication with the groove 3 Ib in the valve mem-y ber 29h.

'I'he valve member 29b isyso constructed that the downward dynamic ow reaction tending to urge the valve toward closed position will increase more rapidly than in the preceding forms upon an increase in the rate of flow so as to eiiect rapid closing. The ports 32b in the valve member 29b and the ports 53 in the sleeve 5I are radially inclined inwardly toward the closed end of the valve member, and the latter is formed intermediate' the ports 32b with a curved central uid will have an increased longitudinal component tending to close the valve.

I claim as my invention:

1. A relief valve comprising, in combination, a valve body having a valve bore, a pressure inlet opening to lthe side of said bore and a relief outlet. a pressure responsive valve member reciprocable in said bore and having a port in the periphery movable into and out of communication with said inlet and a longitudinal bore closed at one end and establishing communication through the other endbetween said port and said outlet, saidbody being formed with s, pressure chamber f open Ato one endof said bore and a passage con- :necting said inlet to said chamber, said valve member having a pressure area at one end exposed to the pressure in said chamber, spring means acting on the other end of said valve member in a direction to close said valve in opposition to said pressure, said port opening to said longitudinal bore at an angle inclined radially inwardly toward the closed end of said longitudinal bore, and a baille in the closed end of l said longitudinal bore for directing the fluid issuingfrom said port through a sharp turn and then longitudinally out of said valve member to said outlet. l

2. A relief valve comprising, in combination, an elongated body having a large bore in one end and a small valve bore opening coaxially to the 3b inner end of said large bore and having an outlet passage opening from said large bore, the outer end of said valve bore dening a pressure chamber and said valve bore being formed intermediate its ends with an inlet port connected through a restricted flow passage to said chamber, a branch passage opening from said inlet port in parallel with said restricted passage to said chamber, a one-way check valve in said branch passage for admitting iiuid to said chamber, a valve member movable in said valve bore with a sliding fit and formed with a longitudinal passage opening to said\ large bore and with a peripheral valve port opening to said longitudinal passage, one end yof said valve member presenting a closed end surface exposed to the pressure in Vsaid chamber tending to move said 'valve member in a direction to bring said ports into communication, and a coiled compression spring in said large bore acting on said valve member in a direction opposite to said first mentioned direction, the kinetic energy created by the change of direction of flowthrough said valve member supplementing lthe pressure of said spring to act on said valve member in opposition to the pressure in said chamber.

3. A relief valve comprising, in combination, a body having a valve bore opening at one end to a pressure chamber and at the other end to a spring chamber and formed with inlet ports rao dially inclined upwardly and outwardly with respect to the pressure chamber end of said bore,

ysaijdesllvring opening to said last mentioned bore and mov- I .able into and out of .ing to said last a valve member reciprocable in said bore closed at the end adjacent said pressure chamber and formed with an axial bore opening to said spring chamber and with peripheral ports opening to said last mentioned bore and movable in-to and out of communication with said iirst mentioned ports and radially inclined in the same direction as said inlet ports, coiled compression spring means disposed in said spring chamber and acting on said valve member to urge said member in said one direction toward closed position, passage means ior directing fluid from said inlet ports to said pressure chamber to act on the l closed end of said valve member in opposition to the force of said spring means and the kinetic energy acting in the direction of the spring force generated by the fluid in said last mentioned bore, and a balde at the inner endeof said last mentioned bore for directingeiluidfrom said last mentioned ports outwardly -toward said spring charnber.

4. A relief valve comprising, in combination, a body having a valve bore opening at one end to a pressure chamber and at the other end to a spring chamber and formed with inlet ports radiallyjnclined in onedirection longitudinally of said bore, a valve member reciprocable in said bore and formed with an axial bore opening to chamber and with peripheral ports y communication with said inletports and radially inclined in said one direction, coiled compression spring means disposed in said spring chamber and acting on said valve memberr to urge said member in said one direction toward closed position. and passage means for directing iluid from said inlet ports to said pressure chamber to act on said valve member in opposition to the force of said spring means and the kinetic energy acting in the direction of the spring torce generated by the fluid in the bore of said valve member.

5. A relief valve comprising, in combination. a body having a valve bore opening at one end to a pressure chamber and at the other end to a spring chamber and formed with a pressure inlet.

a valve sleeve fixed in said bore and formed with inlet ports in communication with said inlet and radially inclined in one direction longitudinalLv ci said bore, a valve member reciprocable in said sleeve and formed with an axial bore opening to said spring chamber and with valve ports openmentioned bore and adapted Yfor communication with said inlet ports and radially inclined in said direction, coiled compression .springmeans disposed in said spring chamber and acting on said valve member to urge said member in said one direction. and a restricted passage for directing fluid from said'inlet to said pressure chamber to act on saidl valve member in opposition to the force of said spring means.

' A. MATHYS. 

